WATER THE KEY COMPONENT FOR LIFE - Water is the only common compound that exists in solid, liquid, and gas phase under ordinary, natural conditions. Water resists extreme temperature changes. This is important for weather and also species survival. Water is the most abundant molecule on the Earth's surface and one of the most important molecules to study in chemistry. Water is a chemical compound. Each molecule of water, H2O or HOH, consists of two atoms of hydrogen bonded to one atom of oxygen. Cohesion a key property of water. Because of the polarity of the molecules, water molecules are attracted to each other. Hydrogen bonds form between neighboring molecules. Because of its cohesiveness, water remains a liquid at normal temperatures rather than vaporizing into a gas. Cohesiveness also leads to high surface tension.

Water is one of the most important molecules in chemistry, particularly biochemistry since water is essential for life. .

Water - The Key Component For Life

Properties of Water

Interesting Facts and Properties of Water

by Anne Marie Helmenstine, Ph.D.

Water is the most abundant molecule on the Earth's surface and one of the most important molecules to study in chemistry.

Here's a look at some facts about water chemistry.

What Is Water?

Water is a chemical compound. Each molecule of water, H₂O or HOH, consists of two atoms of hydrogen bonded to one atom of oxygen.

Properties of Water

There are several important properties of water that distinguish it from other molecules and make it the key compound for life:

1.    Cohesion a key property of water. Because of the polarity of the molecules, water molecules are attracted to each other. Hydrogen bonds form between neighboring molecules.

    Because of its cohesiveness, water remains a liquid at normal temperatures rather than vaporizing into a gas. Cohesiveness also leads to high surface tension.

    An example of the surface tension is seen by beading of water on surfaces and by the ability of insects to walk on liquid water without sinking.

2.    Adhesion is another property of water. Adhesiveness is a measure of water's ability to attract other types of molecules.

    Water is adhesive to molecules capable of forming hydrogen bonds with it. 

    Adhesion and cohesion lead to capillary action, which is seen when the water rises up a narrow glass tube or within the stems of plants.

3.    The high specific heat and high heat of vaporization mean a lot of energy is needed to break hydrogen bonds between water molecules.

    Because of this, water resists extreme temperature changes. This is important for weather and also species survival.

    The high heat of vaporization means evaporating water has a significant cooling effect. Many animals use perspiration to keep cool, using this effect.

4.    Water may be called the universal solvent because it is able to dissolve many different substances.

5.    Water is a polar molecule. Each molecule is bent, with the negative charged oxygen on one side and the pair of positive-charged hydrogen molecules on the other side of the molecule.

6.    Water is the only common compound that exists in solid, liquid, and gas phase under ordinary, natural conditions.

7.    Water is amphoteric, which means it can act as both an acid and a base. Self-ionization of water produces H⁺ and OH^- ions.

8.    Ice is less dense than liquid water. For most materials, the solid phase is denser than the liquid phase.

Hydrogen bonds between water molecules are responsible for the lower density of ice. An important consequence is that lakes and rivers freeze from the top down, with ice floating on water.

Water Facts

·         Other names for water are: dihydrogen monoxide, oxidane, hydroxylic acid, and hydrogen hydroxide

·         the molecular formula of water: H₂O

·         molar mass of water: 18.01528(33) g/mol

·         density 1000 kg/m³, liquid (4 °C) or 917 kg/m³, solid. This is why ice floats on water.

·          melting point: 0 °C, 32 °F (273.15 K)

·          boiling point: 100 °C, 212 °F (373.15 K)

·          acidity (pKa): 15.74

·          basicity (pKb): 15.74

·          refractive index: (nD) 1.3330

·          viscosity: 0.001 Pa s at 20 °C

·          crystal structure: hexagonal

·          molecular shape: bent

·         Pure liquid water at room temperature is odorless, tasteless and nearly colorless. Water has a faint blue color, which becomes more apparent in large volumes of water.

·         Water has the second highest specific enthalpy of fusion of all substance (after ammonia). The specific enthalpy of fusion of water is 333.55 kJ·kg−1 at 0 °C.

·         Water has the second highest specific heat capacity of all known substances. (Ammonia has the highest specific heat.)

Water also has a high heat of vaporization (40.65 kJ·mol−1). The high specific heat and heat of vaporization result from the high degree of hydrogen bonding between water molecules.

One consequence of this is that water is not subject to rapid temperature fluctuations. On Earth, this helps to prevent dramatic climate changes.

Anne Helmenstine, Ph.D., is an author and consultant with a broad scientific and medical background.

Experience

Anne has taught chemistry, biology, and physics at the high school, college, and graduate level. In her doctoral work, Anne developed ultra-sensitive chemical detection and medical diagnostic tests. She has worked abstracting/indexing diverse scientific literature for the Department of Energy. She presently works as a freelance writer and scientific consultant. She enjoys adapting lab-based science projects so that they can be performed safely at home.

Education

Dr. Helmenstine has bachelor of arts degrees in physics and mathematics with a minor in chemistry from Hastings College in Nebraska and a doctorate of philosophy in biomedical sciences from the University of Tennessee at Knoxville.

Anne Marie Helmenstine, Ph.D.

Chemistry is part of everyone's life, from cooking and cleaning to the latest computer chip technology and vaccine development. It doesn't have to be intimidating and it doesn't have to be hard to understand.

You can read more about Anne's current and past work on her Google Profile: Anne Helmenstine. Find Anne's printable periodic tables and science projects at Science Notes.

https://www.thoughtco.com/water-chemistry-facts-and-properties-609401 

GASOLINE - The numerous processes and agents invented to improve the quality of gasoline -The processes that were invented to improve the yield of gasoline from crude oil were known as cracking. In petroleum refining, cracking is a process by which heavy hydrocarbon molecules are broken up into lighter molecules by means of heat, pressure, and sometimes catalysts.

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Gasoline

History of Gasoline

The numerous processes and agents invented to improve the quality of gasoline

By Mary Bellis

Gasoline was not invented, it is a natural by-product of the petroleum industry, kerosene being the principal product.

Gasoline is produced by distillation, the separating of the volatile, more valuable fractions of crude petroleum.

However, what was invented were the numerous processes and agents needed to improve the quality of gasoline making it a better commodity.

The Automobile

When the history of the automobile was heading in the direction of becoming the number one method of transportation. There was created a need for new fuels. In the nineteenth centure, coal, gas, camphene, and kerosene made from petroleum were being used as fuels and in lamps. However, automobile engines required fuels that needed petroleum as a raw material. Refineries could not convert crude oil into gasoline fast enough as automobiles were rolling off the assembly line.

Cracking

There was a need for improvement in the refining process for fuels that would prevent engine knocking and increase engine efficiency. Especially for the new high compression automobile engines that were being designed.

The processes that were invented to improve the yield of gasoline from crude oil were known as cracking. In petroleum refining, cracking is a process by which heavy hydrocarbon molecules are broken up into lighter molecules by means of heat, pressure, and sometimes catalysts.

Thermal Cracking - William Meriam Burton

Cracking is the number one process for the commercial production of gasoline. In 1913, thermal cracking was invented by William Meriam Burton, a process that employed heat and high pressures.

Catalytic Cracking

Eventually, catalytic cracking replaced thermal cracking in gasoline production. Catalytic cracking is the application of catalysts that create chemical reactions, producing more gasoline. The catalytic cracking process was invented by Eugene Houdry in 1937.

Additional Processes

Other methods used to improve the quality of gasoline and increase its supply including:

·                  Polymerization: converting gaseous olefins, such as propylene and butylene, into larger molecules in the gasoline range

·                  Alkylation: a process combining an olefin and a paraffin such as isobutane

·                  Isomerization: the conversion of straight-chain hydrocarbons to branched-chain hydrocarbons

·                  Reforming: using either heat or a catalyst to rearrange a molecular structure

Timeline of Gasoline and Fuel Improvements

·                  19th-century fuels for the automobile were coal tar distillates and the lighter fractions from the distillation of crude oil.

·                  On September 5, 1885, the first gasoline pump was manufactured by Sylvanus Bowser of Fort Wayne, Indiana and delivered to Jake Gumper, also of Fort Wayne. The gasoline pump tank had marble valves and wooden plungers and had a capacity of one barrel.

·                  On September 6, 1892, the first gasoline-powered tractor, manufactured by John Froelich of Iowa, was shipped to Langford, South Dakota, where it was employed in threshing for approximately 2 months. It had a vertical single-cylinder gasoline engine mounted on wooden beams and drove a J. I. Case threshing machine. Froelich formed the Waterloo Gasoline Tractor Engine Company, which was later acquired by the John Deere Plow Company.

·                  On June 11, 1895, the first U.S. patent for a gasoline-powered automobile was issued to Charles Duryea of Springfield, Massachusetts.

·                  By the early 20^th century, the oil companies were producing gasoline as a simple distillate from petroleum.

·                  During the 1910s, laws prohibited the storage of gasoline on residential properties.

·                  On January 7, 1913, William Meriam Burton received a patent for his cracking process to convert oil to gasoline.

·                  On January 1, 1918, the first U.S. gasoline pipeline began transporting gasoline through a three-inch pipe over 40 miles from Salt Creek to Casper, Wyoming.

·                  Charles Kettering modified an internal combustion engine to run on kerosene. However, kerosene-fueled engine knocked and would crack the cylinder head and pistons.

·                  Thomas Midgley Jr. discovered that the cause of the knocking was from the kerosene droplets vaporizing on combustion. Anti-knock agents were researched by Midgley, culminating in tetra ethyl lead being added to fuel.

·                  On February 2, 1923, for the first time in U.S. history ethyl gasoline was marketed. This took place in Dayton, Ohio.

·                  In 1923, Almer McDuffie McAfee developed the petroleum industry's first commercially viable catalytic cracking process, a method that could double or even triple the gasoline yielded from crude oil by then-standard distillation methods.

·                  By the mid-1920s, gasoline were 40 - 60 Octane.

·                  By the 1930s, the petroleum industry stopped using kerosene.

·                  Eugene Houdry invented the catalytic cracking of low-grade fuel into high test gasoline in 1937.

·                  During the 1950s, the increase of the compression ratio and higher octane fuels occurred. Lead levels increased and new refining processes (hydrocracking) began.

·                  In 1960, Charles Plank and Edward Rosinski patented (U.S. #3,140,249) the first zeolite catalyst commercially useful in the petroleum industry for catalytic cracking of petroleum into lighter products such as gasoline.

·                  In the 1970s, unleaded fuels were introduced.

·                  From 1970 until 1990 lead was phased out.

·                  In 1990, the Clean Air Act created major changes on gasoline, rightfully intended to eliminate pollution.

Mary Bellis has been writing about inventors since 1997. She also loves to tinker (invent) and spends too much time in her workshop developing her ideas.

Experience

Forbes Best of the Web credits Mary for creating the number one online destination for information about inventors and inventions. Her writing has been reprinted and referenced to in numerous educational books and articles. Her opinion and advice is requested by media outlets on a constant basis. In addition, she has produced and directed a number of films, including a documentary on Alexander Graham Bell, the inventor of the telephone, and has worked as a curator specializing in computer generated art.

Education

Mary has two degrees in film and animation from the San Francisco Art Institute. She is a big fan of both history and technology and an avid reader of books and periodicals on those topics.

Mary Bellis

I have a passion for inventing and a deep respect for all inventors. I know firsthand the difficulties that inventors face and I want to help by making the path from idea to marketplace a clearer process.

https://www.thoughtco.com/history-of-gasoline-1991845

REVERSE OSMOSIS DESALINATORS - One way to desalinate water is through reverse osmosis with a reverse osmosis desalinator. This filtration process uses pressure to force water through a membrane. The solute (salt) remains on one side of the membrane, while the pure solvent (freshwater) passes to the other side. The solvent (in this case, water) moves from an area of high solute concentration to an area of low solute concentration.

"Water, water, everywhere / nor any drop to drink"
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Reverse Osmosis Desalinators

How Reverse Osmosis Desalinators Work

BY SARAH WINKLER

 

You're setting out for a backpacking expedition and packing up the important gear you'll need for your trip.

You've got your compass, a map, some comfortable hiking boots, some snacks and an army knife. Seems like you have everything you'll need, right?

Well, you're missing one important item that could save your life in a pinch: a way to purify water.

Without water, you're susceptible to dehydration, hypothermia or altitude sickness.

A water purification system like a filter or charcoal tablets could provide you with the purified water you'll need to survive in the outdoors.

But what if you need to do more than purify the water?

What if your only available water sources are saltwater? (Or as Samuel Taylor Coleridge put it in his poem "The Rime of the Ancient Mariner": "Water, water, everywhere / nor any drop to drink.")

Although seawater might look tempting, its high level of salt makes it unsuitable for human consumption.

Average ocean seawater contains three times the salt content found in a person's bloodstream. If you drink seawater, you'll become even more dehydrated, which could lead to seizures, kidney failure or even brain damage and death [source: Seawater Facts].

If you're in the outdoors and the only available water is seawater, then you'll need to desalinate the water; that is, you'll need to reduce the salt content of the water.

One way to desalinate water is through reverse osmosis with a reverse osmosis desalinator. This filtration process uses pressure to force water through a membrane.

The solute (salt) remains on one side of the membrane, while the pure solvent (freshwater) passes to the other side.

The solvent (in this case, water) moves from an area of high solute concentration to an area of low solute concentration.

While osmosis was discovered as early as the 1700s, it wasn't until the 1960’s that scientists were able to use the process to desalinate water [source: Water and Waste Digest].

As its name indicates, this process is the reverse of normal osmosis, in which a solvent moves with no added pressure from an area of low solute concentration to an area of high solute concentration.

Not only does a reverse osmosis desalinator remove salt from water, but it also eliminates harmful bacteria and microorganisms.

The Science of Reverse Osmosis Desalinators

To understand the science of reverse osmosis desalinators, you should first become acquainted with a few key terms:

Desalination: Desalination is simply the process of removing salt content from water.

During this separation process, the dissolved salt in water is reduced to make the water usable.

Although seawater is the largest source of water on our planet, it can't be used for drinking due to its high salt content. Desalination makes seawater fit for human consumption.

Osmosis: Osmosis is a natural phenomenon that affects a variety of biological functions in all forms of life.

Osmosis does everything from allow plants to absorb nutrients from the soil to help the kidneys purify blood.

An osmotic membrane, a membrane that allows water to pass through at higher levels than it does salt, allows for osmosis to occur.

An osmotic membrane is semipermeable; that is, it allows some substances to pass through while others do not.

Although pure water can flow freely in both directions, salt and other impurities can't pass through.

During osmosis, solvent water passes through a semi-permeable membrane toward a concentrated substance on the other side until the osmotic pressure across the membrane is equal (usually 350 pounds per square inch gauge, or psig., freshwater/seawater) [source: Water and Waste Digest].

Reverse osmosis: Reverse osmosis is just like it sounds -- the exact opposite of osmosis.

While in osmosis, solvent water passes through a membrane until the pressure across the membrane is equal, during reverse osmosis, a force with pressure greater than the osmotic pressure is needed to allow freshwater to pass through the membrane while salt is held back.

The higher the pressure is above osmotic pressure, the more quickly freshwater will move across the membrane.

So, a reverse osmosis desalinator combines these processes to make saltwater drinkable. On the next page, we'll take a closer look at the reverse osmosis desalination process.

Desalination Process

During reverse osmosis, saltwater is forced through a semipermeable membrane that allows water molecules to pass through while all other impurities, including salt, are held back.

Here's a look at the step-by-step process of reverse osmosis desalination:

1. To set up a reverse osmosis desalinator, you first need an intake pump at the source of the seawater.

2. Next, you need to create flow through the membrane. This will cause water to pass through the salted side of the membrane to the unsalted side.

Pressure comes from a water column on the salted side of the membrane. This will both remove the natural osmotic pressure and create additional pressure on the water column, which will push the water through the membrane.

Generally, to desalinate saltwater, you need to get the pressure up to about 50 to 60 bars [source: Lentech].

3.    Feed water is then pumped into a closed container. As the water passes through the membrane, the remaining feed water and salt solution become more concentrated.

To reduce the concentration of the remaining dissolved salts, some of the feed water and salt solution is taken out of the container because the dissolved salts in the feed water would continue to increase and thus require more energy to overwhelm the natural osmotic pressure.

4.    Once water is flowing through the membrane, and the pressure is equal on both sides, the desalination process begins.

After reverse osmosis has occurred, the water level will be higher on the side where salt was added.

The difference in water level is caused by the addition of the salt and is called osmotic pressure; generally, the osmotic pressure of seawater is 26 bars.

The quality of water is determined by the pressure, the concentration of salts in the feed water, and the salt permeation constant of the semi-permeable membrane.

To improve the quality of the water, you can do a second pass of membrane.

Once the freshwater and saltwater are separated, the freshwater should be stabilized; that is, the pH should be tested to make sure it's fit for consumption.

Using Reverse Osmosis Desalinators

Reverse osmosis desalinators can operate on both large and small scales.

A backpacker or boating enthusiasts can purchase a reverse osmosis desalination system for personal use, or they can be acquired by larger industrial or community groups in need of freshwater.

Many communities in equatorial zones, arid environments and coastal areas are good candidates for reverse osmosis desalination systems because they generally have available seawater but lack freshwater. For example, places like California, Florida, the Caribbean, Central and South America, the Mediterranean, the Middle East and the Pacific Rim are areas in which reverse osmosis desalination could be a viable option for the production of freshwater on a large scale.

In comparison to two other desalination processes, distillation and freeze-thawing, reverse osmosis is the most cost effective and energy efficient.

For example, while distillation require 30-186 horsepower of mechanical energy to remove one gallon (3.7 liters) of water from saline solution, reverse osmosis desalination only needs about 0.5-1.4 horsepower [source: Desalination: FAQ].

In addition to being energy efficient, reverse osmosis desalinators are also smaller in size than other desalination units.

On a larger scale, they are also less costly to purchase and operate.

Most desalinators are run by electricity; however, if electricity is not available or too expensive, you can also use a diesel or solar-powered desalinator.

Although solar powered desalinators are initially more expensive to purchase, the energy savings may pay off in the end.

To take care of your reverse osmosis desalinator, make sure to keep an eye on the day-to-day operation of the system.

Make sure to adjust the calibration and pumps for leaks or structural damage.

The main problem that you can run into with reverse osmosis desalinators is fouling, when membrane pours become clogged.

To prevent fouling, clean the unit every four months or so and replace filter elements about once every eight weeks.

https://adventure.howstuffworks.com/survival/gear/reverse-osmosis-desalinators.htm